SQL/MX 2.x Query Guide (H06.04+, J06.03+)

SQL/MX Operators
HP NonStop SQL/MX Query Guide—540437-005
7-44
MultiUnion Operator
prepare xx from
select * from table_a
union
select * from table_c;
DESCRIPTION
fragment_id ............ 0
parent_frag ............ (none)
fragment_type .......... master
union_type .............. merge
MultiUnion Operator
N-ary Group
The MultiUnion operator provides performance enhancement for queries that have a
large number of table unions. It denotes a single relational union operator with multiple
children. Its children can be any relational operators that are attached to the union
backbone.
The description field for this operator contains:
The example of the MultiUnion operator is based on:
create table tabl3 (a int, b int, c int,d int, e int);
prepare xx from select * from tabl3 union all
select * from tabl3 union all
select * from tabl3 union all
select * from tabl3 union all
select * from tabl3;
DESCRIPTION
fragment_id ............ 0
parent_frag ............ (none)
fragment_type .......... master
union_type ............. PhyMultiUnion
NESTED_ANTI_SEMI_JOIN Operator
Join Group
The NESTED_ANTI_SEMI_JOIN operator describes a portion of an execution plan
that involves a nested join. This operator returns all rows from the inner table that do
not satisfy the predicates. See NESTED_JOIN Operator on page 7-45.
Note. The MultiUnion operator is supported only on systems running J06.08 and later J-series
RVUs and H06.19 and later H-series RVUs.
Token Followed by ... Data Type
union_type PhyMultiUnion text